#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define endl '\n'

const int nn = 1e5 + 17, mod = 1e9 + 7;
int n, A[nn], B[nn];

void Try() {
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> A[i];
    }
    
    for (int i = 1; i <= n; i++) {
        cin >> B[i];
    }
    
    ll ans = 0;
    priority_queue<int, vector<int>, greater<int>> Mn;
    
    int mx = 0;

    
    for (int i = n; i >= 1; i--) {
        mx = max(mx, B[i]);
        B[i] = mx;
    }
    
    for (int i = 1; i <= n; i++) {
        ans += max(0, B[i] - A[i]);
    }
    
    
    cout << ans << endl;
}

int32_t main() {
    ios_base::sync_with_stdio(0); cin.tie(0);

    int t = 1;
    cin >> t;
    for (int i = 1; i <= t; i++) {
        Try();
    }

}